Abstract
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Objectives N-methyl-11C-methylaminoisobutylric acid (MeAIB) is a promising amino acid PET tracer in urinary diseases, where 18F-fluorodeoxyglucose (FDG) is known to have a poor diagnostic ability. The aim of this study was to evaluate the capability of MeAIB PET/CT, FDG PET/CT, and MR imaging to discriminate aggressive tumors in patients with prostate cancer.
Methods Thirty-six men (age range, 57-77 years) with prostate cancer underwent MeAIB PET/CT, FDG PET/CT, and MR scans between January 2011 and February 2013. MeAIB PET/CT and FDG PET/CT were performed at 20 and 60 min post-injection, respectively. MR examinations included T1WI, T2WI, and DWI. Each modality was assessed visually. All patients subsequently underwent total prostectomy; imaging findings were compared with the histological specimen and the Gleason score.
Results Prostate cancer was confirmed in all surgically-treated patients with the following findings: Stage 2 (n=23), 3 (n=7), and 4 (n=3); Gleason sum score 6 (n=13), 7 (n=15), 8 (n=3), and 9 (n=2). MeAIB PET/CT, FDG PET/CT, and MR imaging were positive in 48% (16/33), 42% (14/33), and 52% (17/33) of patients, respectively. To discriminate aggressive tumors (Gleason sum score ≥7), the patient-based sensitivities of MeAIB PET/CT, FDG PET/CT, and MR imaging were 65%(13/20), 65%(13/20), and 80% (16/20), respectively; the patient-based specificities of MeAIB PET/CT, FDG PET/CT, and MR imaging were 76.9% (10/13), 92.3% (12/13), and 92.3% (12/13), respectively.
Conclusions The sensitivity and specificity for the detection of aggressive prostate cancer were higher with MR imaging than with MeAIB PET/CT or FDG PET/CT.